1. Field of the Invention
This invention relates to a method for producing a semiconductor device by dicing a semiconductor wafer covered with a protective sheet along scribe lines, a semiconductor device produced by the method, and a wafer detachment apparatus usable for the method.
2. Description of the Related Art
As disclosed in many documents such as JP-A-10-242253, JP-A-7-99172, U.S. Pat. Nos. 5,824,177, and 5,362,681, when a semiconductor wafer having plural movable portions is divided into plural chips, a protective sheet is attached to the semiconductor wafer to protect the movable portions. In this state, the semiconductor wafer is diced into the chips together with the protective sheet at a dicing-cut step.
In the conventional method described above, however, because the protective sheet is diced together with the semiconductor wafer, scraps of the protective sheet such as adhesive organic particles are produced by cutting and attached to the chips as contaminants. The scraps may be attached to electrodes formed on each chip to adversely affect the electrodes in electrical and mechanical connection.
Further, in the conventional method, the protective sheet needs to be removed from the chips after the dicing-cut step is carried out. If the protective sheet is bonded to the semiconductor wafer firmly, the removal of the protective sheet is difficult and may cause damage to the chips due to the resulting stress. Therefore, the protective sheet is bonded to the semiconductor wafer with a relatively small amount of adhesion. Because of this, the protective sheet is easily separated from the semiconductor wafer during the dicing-cut step. As a result, the protective layer cannot protect the movable portions sufficiently.